The underwater
Nikonos IVA has gone through some major improvement to the Nikonos design. This is
not surprising as the Nikon SLRs have also been been greatly improved on all other
aspects. One of the most significant development was the inclusion of auto exposure
(the "A" behind the IV signifies auto-exposure), extended film speed range
which is now 25 to 1600 ISO as well as at the flash photography section. The shutter
was still deploying a vertical traveled, metal focal plane type with working shutter
speeds improved slightly from 1/30 sec to 1/1000 sec. (and Bulb) + a backup mechanical
shutter speed at 1/90 sec (M setting), should the battery fails or situation when
facing with power depletion. Flash synchronization: Cable connection with adapter
for electronic flash synch also has been improved to 1/90 sec (Automatic flash control
with Nikonos electronic flash units). It weighs heavier than its predecessor at 900g.
It was also the first Nikonos that incorporated with a built-in light sensor and
offer an aperture priority exposure control. Other improvements included are a side-hinged
back cover, rapid film advance lever, an Albada-type viewfinder with an easy to read,
bright LEDs display as well as a flash ready light inside the finder. Initial production
serial that can be traced was believed to be from 410xxxx and the IVA was discontinued
in 1984.

Commercially,
this all-weather Nikonos was perhaps the most successful model among al the Nikonos
family of underwater camera. It inherited many basic features of the IVa with other
refinements made to its features. The Film speed range remained the same at 25 to
1600 ISO with a quartz-timed, stepless shutter speed range from 1/30 to 1/1000 sec.,
a time-exposure at B setting and a back-up mechanical shutter speed of 1/90 sec.
(M90). It offers both TTL center-weighted metering, auto-exposure (Aperture Priority
AE) as well as Manual exposure control. The Albada finder has parallax markings,
LEDs for exposure readings, low shutter speed warning as well as flash ready light.
The most significant improvement made was the TTL auto flash exposure control with
other applicable Nikonos speedlights such as SB-102, SB-105 etc. making flash photography
results the underwater so easy & assuring. Along with other features made to
improve its overall handling under or above the water, Nikon has designed one of
the most friendly underwater camera in the Nikonos V.